An evaluation of synthetic and natural supravital stains for the cytological examination of dissociated cells in a microfluidic channel.

Abstract

Advances in biotechnology will result in paradigm shifts in both oncology and diagnostics. In pathology, methods such as microfluidics are being explored as delivery tools so that processed cells can serve dual purposes: conventional cytology-based diagnostics and recovery of the same cells for molecular assays. This wet mount-based approach to diagnosis will require staining of these cells by supravital dyes. This study was undertaken to determine the optimal supravital stain for the examination of cells in the wet mount preparations present in microfluidic platforms. Cells were dissociated from portions of tissue similar in size to a traditional core biopsy. These tissue-free cells were separately examined with two synthetic dyes and two natural dyes at varying dilutions. Different dilutions of the synthetic dyes toluidine blue and methylene blue resulted in varying degrees of staining, whereas different dilutions of the natural dyes resulted in fairly constant intensities of colour. These characteristics affected the visualization of cells in wet mount preparations: optimally titered synthetic dyes gave better nuclear detail and cytoplasmic contrast. All four dyes stained the test cells, but to different degrees and intensities. In our assessment, optimally titered synthetic dyes were better suited to the wet mount approach of microfluidics when compared with natural dyes.